The present invention relates to a process for polymerizing and copolymerizing fluorinated monomers, in an aqueous dispersion, in the presence of radicalic starters, characterized in particular by a polymerization rate which is much higher than the one attainable in the conventional processes under analogous operative conditions.
As is well known, the fluoroolefins have each a different reactivity in the polymerization processes, some of them having a very low or no reactivity when compared with tetrafluoroethylene (TFE). Reference can be made in this connection for example to C.sub.3 F.sub.6.
Also some perfluorovinylethers exhibit a very low reactivity in polymerization as compared with other fluoroolefins, in particular TFE.
This behaviour leads to the fact that in order to prepare copolymers from comonomers having a very different reactivity from one another, it is necessary to operate with a high concentration of the less reactive monomer and therefore to operate at a very high partial pressure of said comonomer.
For example, when the thermoplastic copolymer C.sub.2 F.sub.4 --C.sub.3 F.sub.6 (FEP) with 5%-25% by weight of C.sub.3 F.sub.6 is to be prepared, it is necessary to operate with a high concentration of C.sub.3 F.sub.6 in the gas phase corresponding to a total pressure of the monomers from 35 to 40 kg/cm.sup.2 abs. (See U.S. Pat. No. 3,132,124).
There was the requirement to increase the polymerization rate for the low reactive monomers in order to avoid to operate at very high pressures and in order to shorten, at the same time, the polymerization times.